The objective of this project is to further characterize the biodegradation of environmental pollutant by white rot fungi. The proposed experiments reflect some recent findings that are extremely important with respect to the mechanism of degradation and consequently the design of degradation systems. These factors must be appreciated and understood in order to realize the potential of this biodegradation system. How these factors are involved in the mineralization of most environmental pollutants became obvious when we realized that many chemicals may require some reductive steps before oxidation can occur. Secondly, we realized the importance of these factors when we discovered how reduction might occur. Many environmental pollutants are already highly oxidized. For example, the highly chlorinated chemicals like the chlorinated solvents, DDT and PCB, can be considered highly oxidized because they are highly chlorinated. They are therefore difficult to oxidize until they are reduced. Reduction will involve dechlorination, then oxidation can occur. We now know how to catalyze reductions using an electron donor and a free radical mediator (veratryl alcohol). The specific aims of the proposed research therefore are: 1. To determine the concentration of electron donors during the degradation of chemicals in cultures of P. chrysosporium. 2. To determine the concentration of veratryl alcohol or other free radical mediators during degradation of chemicals in cultures of P. chrysosporium. 3. To determine if the concentration of electron donors or free radical mediators are related to the extent of biodegradation. 4. To determine the effect of electron acceptor on the mineralization of chemicals by P. chrysosporium. 5. To determine if P. chrysosporium can mineralize some highly oxidized chemicals. 6. To develop and study a liquid bioreactor for treatment of contaminated water.